1. Field
Example embodiments relate to methods of forming a phase-change material layer pattern, methods of manufacturing a phase-change memory device and related slurry compositions. More particularly, example embodiments relate to methods of forming a phase-change material layer pattern using a chemical mechanical polishing (CMP) process, methods of manufacturing a phase-change memory device and related slurry compositions.
2. Description of the Related Art
Semiconductor memory devices may be generally divided into volatile semiconductor memory devices, e.g., dynamic random access memory (DRAM) devices or static random access memory (SRAM) devices, and non-volatile semiconductor memory devices, e.g., flash memory devices or electrically erasable programmable read only memory (EEPROM) devices. The volatile semiconductor memory device loses data stored therein when the power is turned off. However, the non-volatile semiconductor memory device retains stored data even if the power is turned off.
Among the non-volatile semiconductor memory devices, the flash memory device has been widely employed in various electronic apparatuses, e.g., a digital camera, a cellular phone, and an MP3 player. Because a programming process and a reading process of the flash memory device take a relatively long time, however, technologies to manufacture a semiconductor memory device, for example, a magnetic random access memory (MRAM) device, a ferroelectric random access memory (FRAM) device or a phase-change random access memory (PRAM) device, have been steadily developed.
The phase-change memory device stores information using a resistance difference between an amorphous phase and a crystalline phase of a phase-change material layer composed of a chalcogenide compound, e.g., germanium-antimony-tellurium (GST). Particularly, the PRAM device may store data as states of “0” and “1” using a reversible phase transition of the phase-change material layer. The amorphous phase of the phase-change material layer may have a relatively large resistance, whereas the crystalline phase of the phase-change material layer may have a relatively small resistance.
In the PRAM device, a transistor formed on a substrate may provide the phase-change material layer with a reset current (Ireset) for changing the phase of the phase-change material layer from the crystalline state into the amorphous state. The transistor may also supply the phase-change material layer with a set current (Iset) for changing the phase of the phase-change material layer from the amorphous state into the crystalline state.
In a method of manufacturing a PRAM device, a phase-change material layer pattern may be formed by dry-etching a phase-change material layer which is formed by a deposition process using a chalcogenide compound. However, while the phase-change material layer is patterned by a dry etching process, the phase-change material layer may be damaged by etching plasma, and the damaged portion of the phase-change material layer may generate an operational defect of the PRAM device, e.g., an error of storing data.